1. Field of the Invention
This invention relates to an electro-optical panel such as a liquid crystal panel. More particularly, this invention relates to an electro-optical panel having improved crack resistance by removing scratches and cracks existing on the outer surfaces of glass substrates constituting the electro-optical panel. The invention further relates to a production method of such an electro-optical panel.
2. Related Art
An electro-optical panel such as a liquid crystal panel is fabricated by sandwiching an electro-optical material between two light-transmitting substrates. The light-transmitting substrates are usually glass substrates, and the liquid crystal panel per se has a structure fabricated by bonding two glass substrates to each other.
The liquid crystal panel described above has a problem in that the liquid crystal panel is broken by impact due to scratches and cracks that develop in the glass substrate during a production process.
Such scratches and cracks develop in a production process of the liquid crystal panel including a production step of the glass substrates for the liquid crystal panel, a cutting step of the liquid crystal panel and a conveying step of the glass substrates for the liquid crystal panel. In the production process of the liquid crystal panel, two glass substrates (also called “large sheet glass substrate” and “mother glass substrate”, and hereinafter called “large sheet glass substrate”) are bonded to each other to produce a substrate having a plurality of liquid crystal panels (hereinafter called “large sheet panel substrate”), and each large sheet panel substrate is cut to yield discrete liquid crystal panels. The cutting step of the large sheet glass substrate employs a method that forms cutting lines on a surface of each large sheet glass substrate by use of a cutter, or the like, and applies force along the cutting lines by use of a jig to push and cut the large sheet glass substrate, and a method that irradiates a laser beam along the cutting lines to cut the large sheet glass substrate. In either case, scratches and cracks unavoidably develop on the cut surface of the cut glass substrate (corresponding to the side surface of the liquid crystal panel) and at the corners of the cut surface.
In each process step other than the cutting step described above, scratches and cracks may develop on the glass substrate constituting the liquid crystal panel in many manufacturing steps such as when a robot clamps and conveys the liquid crystal panel and when the liquid crystal panel is fixed to, and moved on, a bench.
Such scratches and cracks develop depending on factors such as the stress applied to the liquid crystal panel, and the dropping of a cellular telephone as a product, for example, results in cracks of the liquid crystal panel.
In view of the problems described above, the invention aims at providing an electro-optical panel having improved crack resistance of a substrate by removing scratches and cracks developed in the substrate during a production process, and a production method thereof.